Interstate 70 is the primary east west artery through the Denver metropolitan area. Many of its bridges and viaducts dated to the early interstate era and were in need of upgrade and replacement. A large portion of I-70 just east of I-25 was elevated on one of these aging viaducts badly in need of structural and capacity improvements. Half of this viaduct had been rebuilt by an earlier project. Major questions remained as to exactly how to replace the second half. The precise alignment was one these questions.

The Colorado Department of Transportation (CDOT) conducted the I-70 East Environmental Impact Study (EIS) to determine the answers. POITRA Visual was selected to provide design visualization services for the project.*

The EIS put forth two alignments that roughly followed the original again on viaduct. Where possible portions of I-70 would be placed on fill and mechanically stabilized earth (MSE) walls similar to those used on the earlier project. The concept would also include terraced curvelinear landscape walls.

POITRA created an aerial visual simulation of the proposed alternatives for I-70 at a later stage in the project.

POITRA illustrated this concept for two alignments with photosimulation in order to compare the alternatives in context. The location chosen for simulation was at a neighborhood school that had potential visual impacts.

A surprizing percentage of the work on this type of simulation occurs when restoring background elements as foreground elements are removed. Unfortunately all that work usually represents a comparatively small area of the overall simulation. ”

M.P., POITRA Visual
Visual Simulations Project Manager

POITRA photographers collected multiple views that would allow the differences in the alternatives to be best described. The Project Engineer made the final view selection. Since two alignments would be simulated two separate base photographs would be required. Each base photograph would have different existing buildings and trees removed and the background restored in addition to removing the existing viaduct and pier columns. This work was accomplished using traditional digital painting techniques.

Modelers at POITRA then created two 3D site models. One modeled the I-70 alignment shift to the north or closer to the school. The other modeled the alignmnent shift south or farther from the school.
The site models included the new viaduct structure, MSE abutment walls and panels, MSE landscape walls and panels, concrete jersey barriers and sound walls. These models were camera matched, lighted, rendered and composited with the appropriately prepared base photograph to create a final photosimulation for each alignment.

CDOT used the finished simulations in I-70 East EIS meetings with the school, the City and County of Denver and area residents during the EIS public process. The simulations also appeared in the Draft EIS document.